Loud-speaker



May 7, 1929. w FF 1,711,939

LOUD SPEAKER Filed April 6, 1925 WITNESS.- /V//// w? 17 ATTOR/VEY.

Patented May 7, 1929.

UNITED STATES WILLIAM H. GRAFF, OF PHILADELPHIA, PENNSYLVANIA.

LOUD-SPEAKER.

Application filed April 6, 1925. Serial No. 20,977.

The principal objects of the present invention are to avoid distortionin the reproduction; to improve the reproduction; to provide for varyingthe degree of loudness of the reproduction; and, in general, to providefor clear, true and accurate reproduo' tion.

The invention will be claimed at the end hereof but will be firstdescribed in connection with the accompanying drawing forming parthereof and in whiclrthej single figure is a view principally in centralsection but showing parts in elevation and parts broken away.

In the drawing there is illustrated a shell of generally heart-shape asat 1. and of gen: erally horn shape as at 2. The large end oi the hornis not shown because it is too well understood to require illustrationand because there is not room on the sheet. 3 is a heart shaped bodyarranged in the heart shaped port-ion 1 of the shell and spaced from-thewall thereof to provide. a sound channel of gradually increasingcross-section or expanding form from the generally flat confrontingportions of the shell and body to the. throat of the horn and thence ofcourse in the horn. This sound channel leads off laterally from thegenerally flat confronting portions of the shell and body. 4 are ribswhich are a means for supporting the body in the shell in the mannerdescribed. 5 is a telephone unit mounted in the body 3 and having adiaphragm 6 en tirely uncovered and exposed to the confronting wall ofthe shell. 7 is an adjustable wall section mounted in the shell andconfronting the diaphragm 6. This adjustable wall 7 may be made toapproach and to recede from the diaphragm by means of the adjustingscrew 8 shown to extend through the wall of the shell and to have itspoint seated upon the adjustable wall section 7. The degree of loudnessof the reproduction can be changed by manipulating the screw 8 in orderto set the wall section 7 nearer to or further from the diaphragm (3 ofthe telephone unit. The sound channel extends laterally from thediaphragm and thence of gradually continually expanding form between thebody 3 and shell and outward through the horn.

Thewheart shaped body 3 may be solid or hollow and may consist of metal,wood or composition.

In the drawing there happens to be shown a structure fitted with fourribs 4. disposed 90 circular degrees apart, so that in the sectionalview two of the ribs -1- appear in full lines at opposite sides. The.third rib being back of the heart shaped body appears in dotted lines.and the fourth rib disappears in the sectional view in which it isassumed to be rcmovcd'along with the half of the shell that is cut away.

It will be obvious to those skilled in the art to which the inventionrelates that modifications may be made in details of construction andarrangement without departing from the spiritof the invention which isnot limited as to those matters or otherwise than as the prior art andthe appended claims may require.

I claim:

1. A loud speaker including a shell of generally heart shape and havinga throat", and a fiat wall, a heart shaped body arranged in the heartshaped portion of the shell and spaced from the wall thereof to providea sound channel leading off laterally and of gradually increasingcross-section from the confronting generally flat portions of the shelland body to the throat, and a telephone unit mounted in the body andhaving :1 diaphragm entirely uncovered and exposed to the confrontinggenerally flat wall of the shell.

2. A loud speaker including a shell of generally heart and horn shape, aheart shaped body arranged in the heart shaped portion of the shell andspaced from the wall thereof to provide a sound channel leading offlaterally and of gradually increasing crosssection from the confrontinggenerally flat portions of the shell and body to the throat of the born,a telephone unit mounted in the body and having a diaphragm entirelyuncovered and exposed to the confronting generally flat wall of theshell, and an adjustable wall section mounted in the shell andconfronting the diaphragm.

WM. H. GRAFF.

